BACKGROUND Recent research suggests that abnormal Ca2+ handling plays a role in the occurrence and maintenance of atrial fibrillation (AF). Therefore, Ca2+ release and ingestion depend on properties of the ryanodine receptor (RyR) and sarcoplasmic reticulum Ca2+ATPase2a (SERCA2a). This study aimed to detect whether SERCA2a gene overexpression has a preventive effect on atrial fibrillation caused by rapid pacing right atrium. MATERIAL AND METHODS Forty-eight New Zealand white rabbits were randomly divided into a control group, AF group, AAV9/GFP group, and AAV9/SERCA2a group...

The mammalian ryanodine receptor Ca(2+) release channel (RyR) has a single conserved high affinity calmodulin (CaM) binding domain. However, the skeletal muscle RyR1 is activated and cardiac muscle RyR2 is inhibited by CaM at submicromolar Ca(2+). This suggests isoform-specific domains are involved in RyR regulation by CaM. To gain insight into the differential regulation of cardiac and skeletal muscle RyRs by CaM, RyR1/RyR2 chimeras and mutants were expressed in HEK293 cells, and their single channel activities were measured using a lipid bilayer method...

To investigate the "methyl" impact on bioactivity of sulfiliminyl dicarboxamides, a total of 16 novel N-cyano and N-trifluoroacetyl sulfiliminyl dicarboxamides containing m-heptafluoroisopropylated aromatic amino moiety were studied. Two series of sulfiliminyl substituents were designed, synthesized and evaluated against oriental armyworm (Pseudaletia separata Walker) for their insecticidal activities. Their chemical structures were established by corresponding [Formula: see text] NMR, HRMS and optical polarimetry...

The present study aimed to investigate the effects of acute sepsis on diaphragm contractility and relaxation, via examining the Ca2+‑uptake function of sarco/endoplasmic reticulum Ca2+ adenosine triphosphatase (SERCA), and the protein levels of SERCA1, SERCA2 and the ryanodine receptor (RyR) of the sarcoplasmic reticulum (SR). A sepsis rat model was established through cecal ligation and puncture (CLP). A total of 6 and 12 h following CLP, the isometric contractile and relaxation parameters of the diaphragm were measured...

Mutations or upregulation in presenilin 1 (PS1) gene are found in familial early-onset Alzheimer's disease or sporadic late-onset Alzheimer's disease, respectively. PS1 has been essentially studied in neurons and its mutation was shown to alter intracellular calcium (Ca(2+)) signals. Here, we showed that PS1 is expressed in smooth muscle cells (SMCs) of mouse cerebral arteries, and we assessed the effects of the deletion of exon 9 of PS1 (PS1dE9) on Ca(2+) signals and contractile responses of vascular SMC. Agonist-induced contraction of cerebral vessels was significantly decreased in PS1dE9 both in vivo and ex vivo...

: Purpose: Red yeast rice (RYR) supplementation has become a popular alternative to statin therapy in treating hypercholesterolemia. This state-of-the-science review seeks to explore the most recent evidence on the effectiveness and safety of RYR supplementation in treating dyslipidemic adults. METHODS: This review extends the time frame of a meta-analysis performed by Li and colleagues in 2014; specifically, we looked at the literature published between September 2013 and April 2016...

Red yeast rice (RYR) is a dietary supplement obtained from rice fermented with the mould Monascus purpureus. It contains Monacolin K which is a hypocholesterolemic statin used to prevent cardiovascular diseases. The homologous prescription biosynthetic statin, lovastatin, is not chemically distinguishable from monacolin K. In this work we investigated whether δ(13)C and δ(2)H can distinguish monacolin K from lovastatin and can detect the presence of lovastatin in RYR. 18 samples of red yeast rice powder and 18 samples of lovastatin were collected...

Emerging evidence suggests that Ca(2+) signals are important for the self-renewal and differentiation of human embryonic stem cells (hESCs). However, little is known about the physiological and pharmacological properties of the Ca(2+)-handling machinery in hESCs. In this study we used RT-PCR and Western blotting to analyze the expression profiles of genes encoding Ca(2+)-handling proteins; we also used confocal Ca(2+) imaging and pharmacological approaches to determine the contribution of the Ca(2+)-handling machinery to the regulation of Ca(2+) signaling in hESCs...

T-wave alternans (TWA) is a potent arrhythmia substrate under the conditions of acute myocardial ischemia. Abnormal intracellular calcium cycling contributes to the genesis of cardiac alternans. Ryanodine receptor (RyR) is a pivotal Ca(2+) cycling protein central to Ca(2+) signaling in the heart. Here, we investigated the potential role of RyR in cardiac alternans and ventricular arrhythmias in acute myocardial ischemia. Transmembrane action potentials were simultaneously recorded from epicardium and endocardium together with a transmural ECG and isometric contraction force in the arterially perfused left ventricular wedge preparations...

Diamide insecticides are used widely against lepidopteran pests, acting as potent activators of insect Ryanodine Receptors (RyRs) and thus inducing muscle contraction and eventually death. However, resistant phenotypes have recently evolved in the field, associated with the emergence of target site resistance mutations (G4946E/V and I4790M). We investigated the frequency of the mutations found in a resistant population of Tuta absoluta from Greece (G4946V ~79% and I4790M ~21%) and the associated diamide resistance profile: there are very high levels of resistance against chlorantraniliprole (9329-fold) and flubendiamide (4969-fold), but moderate levels against cyantraniliprole (191-fold)...

Neuropeptide S (NPS) is a peptide recently recognized to be present in the CNS, and believed to play a role in vigilance and mood control, as behavioral studies have shown it promotes arousal and has an anxiolytic effect. Although NPS precursor is found in very few neurons, NPS positive fibers are present throughout the brain stem. Given the behavioral actions of this peptide and the wide innervation pattern, we examined the cellular effects of NPS within two brain stem nuclei known to play a critical role in anxiety and arousal: the dorsal raphe (DR) and laterodorsal tegmentum (LDT)...

Ryanodine Receptors (RyRs) are intracellular Ca(2+) channels that mediate Ca(2+) flux from the sarco(endo)plasmic reticulum in many cell types. The interaction of RyRs with FK506-binding proteins (FKBPs) has been proposed as an important regulatory mechanism, where the loss of this interaction leads to channel dysfunction. In the heart, phosphorylation of RyR has been suggested to disrupt the RyR-FKBP interaction promoting altered Ca(2+) signaling, heart failure and arrhythmias. However, the functional result of FKBP interaction with RyR and how this interaction is regulated remains highly controversial...

Phthalic acid diamide insecticides are the most effective insecticides used against most of the lepidopteran pests including Helicoverpa armigera, a polyphagous pest posing threat to several crops worldwide. The present studies were undertaken to understand different target sites and their interaction with insect ryanodine receptors (RyR). Bioassays indicated that flubendiamide inhibited the larval growth in dose-dependent manner with LD50 value of 0.72 μM, and at 0.8 μM larval growth decreased by about 88%...

Rajiv Sankaranarayanan, Kornél Kistamás, David J Greensmith, Luigi A Venetucci, David A Eisner

KEY POINTS: For the heart to function as a pump, intracellular calcium concentration ([Ca(2+) ]i ) must increase during systole to activate contraction and then fall, during diastole, to allow the myofilaments to relax and the heart to refill with blood. The present study investigates the control of diastolic [Ca(2+) ]i in rat ventricular myocytes. We show that diastolic [Ca(2+) ]i is increased by manoeuvres that decrease sarcoplasmic reticulum function. This is accompanied by a decrease of systolic [Ca(2+) ]i such that the time-averaged [Ca(2+) ]i remains constant...